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4 structure of a can bus system (example), Canopen, 4 structure of a can bus system – Lenze EMF2175IB User Manual

Page 21

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CANopen

4

Installation

4-5

L

BA2175 EN 2.0

4.4

Structure of a CAN bus system

(Example)

The CAN bus system is designed as 2 conductor type (twisted pair) shielded with additional mass
and termination at both ends of the line (see

(

^

4-6)

).

Data can be send and received as follows:

Max. 3 process data channels (PDO = Process Data Object)

– Process data are send via the process data channel and are used for high-speed and

high-priority control tasks. Typical process data are, for instance, setpoints and actual
values for a controller.

2 parameter data channels(SDO = Service Data Object)
– Parameters are transferred at lower priority than process data. Parameters are set or

changed during, for instance, commissioning or changing the product.

– Parameters are accessed via the parameter data channel of the 2175 fieldbus module to

the Lenze controller codes or corresponding CANopen objects (detailed description in
chapter CANopen parameter setting).

– 2 masters can be connected to the controllers because of the 2 parameter channels. Thus,

parameters can be changed directly at the controller during operation of a machine or
system networked via PLC, using a PC (e.g. with the user software Global Drive Control) or
a keypad. The second parameter data channel can be accessed with an offset of 64 via the
address set (switch or L-C0009). For instance, if a PLC addresses the controller with
address 1 and a second commanding unit address 65, the same controller will be
addressed. Please note that the last telegram determines a parameter when it is accessed
by two units ( see “ Server SDO Parameters”

(

^

6-35)

).

Note!

Please note that the last telegram determines a parameter when it is accessed by two units.

See chapter 5, if you do not use the front switch to enter baud rate and address.

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